1. Field of the Invention
The present invention relates generally to a key or tag for use in an electronic recognition and identification system, and more particularly, to a recognition and identification key having a resonant frequency which is capable of being adapted to a new resonant frequency and a method of adapting same.
2. Description of the Prior Art
Recognition and identification objects in the form of keys, tags, cards or the like are presently used in electronic recognition and identification systems to operate electronic and electrically-controlled locks or to identify articles such as luggage, stored merchandise, vehicles, animals or the like to which they are attached.
Examples of prior electronic recognition and identification systems may be found in U.S. Pat. No. 3,970,824, entitled "Electronic Recognition and Identification System For Identifying A Family Of Codes"; U.S. Pat. No. 3,752,960, entitled "Electronic Identification And Recognition System"; U.S. Pat. No. 3,816,708, entitled "Improved Electronic Recognition And Identification System"; and U.S. Pat. No. 3,842,246, entitled "Recognition And Identification System With Noise Rejection Capabilities".
Heretofore, keys have been formed with inductive and capacitive reactances which are fixed such that the key is operative at a predetermined resonant frequency. As a consequence, the keys have been incapable of modification when operation at a different resonant frequency is desired.
In various applications, it is desirable to have a standard key which is capable of having its code selected to fit a desired lock, or which is capable of being modified corresponding to a change in the responsive identification code of a lock. Such a capability is not realized in mechanical lock and key systems and heretofore in unknown in electronic recognition and identification systems of this type.
Tags for objects have been made in the prior art, but once made there has been no method for readily modifying them to a new code.
Tags and keys manufactured by the prior art could not readily be modified near the conclusion of the manufacturing process to a new code, or adjusted or tuned to a desired final value.